Multiple declaration error shown multiple times

[NeilMitchell]

Given the file:

foo = 1
a = ()
foo = 1
b = ()
foo = 1

You get the error message:

Uniplate.hs:3:0:
    Multiple declarations of `Main.foo'
    Declared at: Uniplate.hs:1:0
                 Uniplate.hs:3:0

Uniplate.hs:5:0:
    Multiple declarations of `Main.foo'
    Declared at: Uniplate.hs:1:0
                 Uniplate.hs:5:0

Instead of the much simpler:

Uniplate.hs:5:0:
    Multiple declarations of `Main.foo'
    Declared at: Uniplate.hs:1:0
                 Uniplate.hs:3:0
                 Uniplate.hs:5:0

This also happens with multiple class definitions, but if you give multiple type signatures then the error message is properly merged.

[simonpj]

Good suggestion. I couldn't resist fixing this. I think we'll leave the fix in the HEAD only though.

Tue May 20 15:30:06 BST 2008  simonpj@microsoft.com
  * Fix Trac #2293: improve error reporting for duplicate declarations

Simon